1. Field of the Invention
The present invention relates generally to warning systems and, more particularly, to an automatic door warning system.
2. Description of the Related Art
With the increased use of public transportation in our society, there has been a corresponding increase in accidents that occur to public transportation passengers. Perhaps the most traumatic of these accidents occur when a passenger tries to board a vehicle in which the doors are closing or are about to close and thus becomes trapped. This action often results in bodily injury, trauma, physical disability or even death.
Further compounding this problem is the fact that most forms of public transportation including trains, trams, trolleys, buses, subway trains, and elevators do not have an operator in close physical proximity to the door. This fact often results in an increased response time to door trapped victims increasing injuries and causing mental trauma to fellow passengers.
While most people would never knowingly subject themselves to direct physical harm, sometimes carelessness and a preoccupation with boarding a vehicle leads to distraction from the dangers. Often the first indication a passenger has that a vehicle is about to move is when the vehicle doors begin to close. At this point the passenger must either rapidly move out of the way, perhaps also causing injury, or rely on numerous prior art door safety devices, which may or may not be operational, to avoid injury.
Numerous attempts have been made to correct for the foregoing problems. For instance, U.S. Pat. No. 5,142,152 to Boiucaner discloses a sliding door sensor. This invention controls the operation of sliding doors so that the doors remain in an open position until the pedestrian traffic clears the door threshold. This action would not be acceptable in many situations such as subway trains where a strict schedule must be adhered to. Moreover, this invention does not address the problem of pre-warning the passenger that the doors are about to close.
Several other attempts have been made at providing an automatic door warning system. For example, U.S. Pat. No. 4,967,083 and No. 4,698,937 to Kornbrekke et al. disclose an invention which utilizes multiple sensor modules either mounted above or on the door itself. Once again, any devices made according to either of the Kornbrekke disclosures only provide for the detection of movement within the door threshold or door swing area and do not address the problem of pre-warning the passenger that the doors are about to close.
Finally, U.S. Pat. No. 4,821,024 to Bayha discloses a door operator pre-warning system and proposes solutions which involve an advance warning system. However, the preferred embodiment disclosure in the Bayha reference only addresses the advance warning problem as would be found on a residential overhead garage door and associated radio frequency link and does not address the problem as would be found on various forms of public transportation.
Consequently, a need has been felt for providing an apparatus and method which provides clear and distinct advance warning messages that automatic doors on various forms of public transportation are about to close.